/*
 * Copyright (C) 2009, 2015-2016 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

#pragma once

#include "include/JavaScriptCore/heap/Weak.h"
#include <wtf/HashMap.h>

namespace JSC {

// A HashMap with Weak<JSCell> values, which automatically removes values once they're garbage collected.

    template<typename KeyArg, typename ValueArg, typename HashArg = typename DefaultHash<KeyArg>::Hash,
            typename KeyTraitsArg = HashTraits<KeyArg>>
    class WeakGCMap {
    WTF_MAKE_FAST_ALLOCATED;
        typedef Weak<ValueArg> ValueType;
        typedef HashMap<KeyArg, ValueType, HashArg, KeyTraitsArg> HashMapType;

    public:
        typedef typename HashMapType::KeyType KeyType;
        typedef typename HashMapType::AddResult AddResult;
        typedef typename HashMapType::iterator iterator;
        typedef typename HashMapType::const_iterator const_iterator;

        explicit WeakGCMap(VM &);

        ~WeakGCMap();

        ValueArg *get(const KeyType &key) const {
            return m_map.get(key);
        }

        AddResult set(const KeyType &key, ValueType value) {
            return m_map.set(key, WTFMove(value));
        }

        bool remove(const KeyType &key) {
            return m_map.remove(key);
        }

        void clear() {
            m_map.clear();
        }

        bool isEmpty() const {
            const_iterator it = m_map.begin();
            const_iterator end = m_map.end();
            while (it != end) {
                if (it->value)
                    return true;
            }
            return false;
        }

        inline iterator find(const KeyType &key);

        inline const_iterator find(const KeyType &key) const;

        template<typename Functor>
        void forEach(Functor functor) {
            for (auto &pair: m_map) {
                if (pair.value)
                    functor(pair.key, pair.value.get());
            }
        }

        inline bool contains(const KeyType &key) const;

        void pruneStaleEntries();

    private:
        HashMapType m_map;
        VM &m_vm;
    };

} // namespace JSC
